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Choose appropriate lock primitives

influxdata/influxdb
Based on 8 comments
Rust

Select lock types based on access patterns - prefer RWLock over Mutex for read-heavy operations to enable concurrent reads while allowing exclusive write access. Minimize lock scope to essential operations and avoid holding locks across await points in async code.

Concurrency Rust

Reviewer Prompt

Select lock types based on access patterns - prefer RWLock over Mutex for read-heavy operations to enable concurrent reads while allowing exclusive write access. Minimize lock scope to essential operations and avoid holding locks across await points in async code.

// AVOID: Using Mutex for read-heavy operations
type MetaData = Mutex<HashMap<String, HashMap<String, ParquetFile>>>; 

// BETTER: Using RWLock for read-heavy operations
type MetaData = RwLock<HashMap<String, HashMap<String, ParquetFile>>>;

// AVOID: Taking lock before doing computation
async fn persist_parquet_file(&self) -> Result<(), Error> {
    // Lock held during entire function including computation
    let mut meta_data_lock = self.meta_data.write();
    // Long computation while holding lock
    let result = compute_expensive_result().await?;
    // Update metadata
}

// BETTER: Taking lock only when needed
async fn persist_parquet_file(&self) -> Result<(), Error> {
    // Do computation without holding lock
    let result = compute_expensive_result().await?;
    
    // Only take lock when updating shared state
    let mut meta_data_lock = self.meta_data.write();
    // Update metadata with minimal lock time
}

For high-contention scenarios, consider specialized concurrent data structures like DashMap that distribute lock contention. Keep related data under the same lock to ensure atomic updates across multiple data structures.

8
Comments Analyzed
Rust
Primary Language
Concurrency
Category

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